U.S. Pat. No. 4,820,330 invented by Jui-Chang Lin discloses a structure for controlling the dead bolt used in an electronic lock which however has the following drawbacks:
1. When the cross rod 441 is to be retreated to the outside of rail 49, the upper round part of the cross rod 441 is moved from the engaged notch 493 of the rail 49 to the inclined way 494 to compress the springs 492 of the rail 49 as urged by the spring 43 jacketed on the moving base 44, thereby easily causing an elastic fatigue of the spring 43 after a long time operation of the lock.
Since the cross rod 441 should be operatively engaged with the grooves 452 of engaging disc 45 and the grooves 463 of the engaging base 46 for opening the lock from the outside knob 11, each groove 452 or 463 is preferably made as an outwardly enlarged arcuate shape for smoothly engaging the cross rod 441. However, such an arcuate groove (port) may not carry the upper round part of the cross rod 441 to sharply match the notch 493 of rail 49 when opening the lock. Once an elastic fatigue is caused to the spring 43, the upper round part of the cross rod 441 even urged by the spring 43 may be frictionally retarded on the rail surface 49 and can not be poked into the notch 493 to engage the grooves 452 of disc 45, unable for opening the lock.
2. So many elements of the base plate 3 and moving parts 4 are provided to increase production cost and maintenance problems of a complete lock. The so many elements of the lock may also increase their production complexity. Also, many elements in construction of the lock may not be operated very smoothly as expected. For instance, the cross rod may not be precisely operated in cooperation with the rail to cause malfunction or false action. So many springs may also be counteracted with each other to easily cause fatigue failure to possibly lose their normal effects, thereby causing the maintenance problems. The present inventor has found such drawbacks and invented the present lock with some improvements thereover.
U.S. Patent Application entitled "Control Mechanism of Electronic Lock" filed on Jan. 22, 90 by the same applicant of this application with a Ser. No. 07/468,058 discloses a locking mechanism provided with only a single latch bolt so that the applicant expects to disclose a lock having a dead bolt and a latch bolt for enhanced security purpose.